The Water Permeability Properties Of Re-Vibrated Lightweight Concrete,
2020
Chulalongkorn University
The Water Permeability Properties Of Re-Vibrated Lightweight Concrete, Muayad Mohammed Kassim
Journal of Metals, Materials and Minerals
Re-vibration of sequential layers of relatively deep structural members after a particular time harms the strength and water permeability properties of the concrete. The harmful effects can be observed in lightweight concrete due to the floating tendency of lightweight aggregate. In this experimental study, the influence of adding retarder plasticizer and silica fume on water permeability properties of re-vibrated lightweight concrete was investigated. The effects of re-vibration at different time lags on compressive strength and permeable voids ratio were studied. Absorption, sorptivity, and water penetration depth under pressure were also studied. Results show that the addition of a retarder increased …
Physical Property And Compressive Strength Of Fired Clay Bricks Incorporated With Paper Waste,
2020
Chulalongkorn University
Physical Property And Compressive Strength Of Fired Clay Bricks Incorporated With Paper Waste, Anuwat Srisuwan, Nonthaphong Phonphuak
Journal of Metals, Materials and Minerals
This research is intended to evaluate the effects of paper waste addition on the physical properties and strength of fired clay bricks. Paper waste was mixed with clay in the ratios of 2.5, 5.0, 7.5 and 10 wt%. Green bricks were fired with different variations of temperature from 900-1100C for1 h in air. Fired bricks were then analyzed for physical and mechanical properties. Porosity was increased with higher paper waste content. An increase in porosity relatedly created lower density and higher shrinkage values. Additionally, porous content in fired clay bricks correlated to the deterioration of the compressive strength, due to …
Structural Studies Of Natural Zeolites And Optimizations For Water Hardness Softening Media,
2020
Chulalongkorn University
Structural Studies Of Natural Zeolites And Optimizations For Water Hardness Softening Media, Tesfamariam Teklu Gebretsadik, Teklit Kidane Gebremedhin
Journal of Metals, Materials and Minerals
This study was aimed at investigating the mineralogical composition and structural features of natural zeolites using XRF, XRD, TGA, FT-IR and SEM. Natural zeolites were subjected to acid-activation and subsequently with NaCl salt to enhance surface area for water hardness softening applications. Peaks around 3560 and 1650 cm-1 belongs to O - H stretching and O - H bending vibrations which confirmed the presence of moisture within zeolite structures. This result was further supported by evolution of moisture above 108°C from thermogravimetric analysis. Fibrous structures which are full of rough texture were examined by SEM. The XRD pattern confirmed Stellerite …
The Design Of A Continuous Wave Molecular Nitrogen Stimulated Raman Laser In The Visible Spectrum,
2020
Air Force Institute of Technology
The Design Of A Continuous Wave Molecular Nitrogen Stimulated Raman Laser In The Visible Spectrum, Timothy J. Bate
Theses and Dissertations
Hollow-core photonic crystal fibers (HCPCFs) shows promise as a hybrid laser with higher nonlinear process limits and small beam size over long gain lengths. This work focuses on the design of a CW molecular nitrogen (N2) stimulated Raman laser. N2 offers Raman gains scaling up to 900 amg, scaling higher than H2. The cavity experiment showed the need to include Rayleigh scattering in the high pressure required for N2 Raman lasing. Even at relatively low pressure ssuch as 1,500 psi, high conversion percentages should be found if the fiber length is chosen based on …
Cn And C2 Spectroscopy On The Pulsed Ablation Of Graphite In The Visible Spectrum,
2020
Air Force Institute of Technology
Cn And C2 Spectroscopy On The Pulsed Ablation Of Graphite In The Visible Spectrum, Brandon A. Pierce
Theses and Dissertations
An experimental study was conducted on the nanosecond pulsed laser ablation of graphite using a KrF laser at a fluence of 3.8 J/cm2 in Air, Ar, He, and N2. Optical emissions spectroscopy revealed the C2 Swan sequences and the CN Violet sequences. A spectroscopic model was developed to extract the molecular rotational and vibrational temperatures of each excited species for t=0.5-10 microseconds after laser irradiation. The rovibrational temperatures were found to vary with background gas for the CN Violet; however, only the vibrational temperature varied between He and the other background gases for C2 Swan. …
Biomimetic Metal-Organic Nanoparticles Prepared With A 3d-Printed Microfluidic Device As A Novel Formulation For Disulfiram-Based Therapy Against Breast Cancer,
2020
Old Dominion University
Biomimetic Metal-Organic Nanoparticles Prepared With A 3d-Printed Microfluidic Device As A Novel Formulation For Disulfiram-Based Therapy Against Breast Cancer, Ya Chang, Jizong Jiang, Wu Chen, Wen Yang, Lili Chen, Pengyu Chen, Jianzhong Shen, Shizhi Qian, Teng Zhou, Linfeng Wu, Liang Hong, Yongzhuo Huang, Feng Li
Mechanical & Aerospace Engineering Faculty Publications
Disulfiram (DSF) is currently tested in several clinical trials for cancer treatment in combination with cop-per (Cu) ions. Usually, DSF and Cu are administered in two separate formulations. In the body, DSF andCu ions form diethyldithiocarbamate copper complex [Cu(DDC)2] which has potent antitumor activities.However, the “two formulation” approach often achieved low Cu(DDC)2 concentration at tumor regions and resulted in compromised anticancer efficacy. Therefore, preformed Cu(DDC)2 complex administered in a single formulation will have better anticancer efficacy. However, the poor aqueous solubility of Cu(DDC)2 is a significant challenge for its clinical use. In this work, a …
Development Of Sr/Cao Catalyst Derived From Cuttlebone (Sepia Officinalis) For Biodiesel Production,
2020
Chulalongkorn University
Development Of Sr/Cao Catalyst Derived From Cuttlebone (Sepia Officinalis) For Biodiesel Production, Napat Tomano, Apisit Prokaew, Supakorn Boonyuen, Sarute Ummartyotin
Journal of Metals, Materials and Minerals
Cuttlebone (Sepia officinalis) was used as a source of calcium oxide for biodiesel catalyst. The objective of this work is to present the bio-based catalyst prepared from cuttlebone. 1, 3, 5 and 10 %wt of strontium was loaded into calcium oxide powder derived from cuttlebone. Structural properties of Sr/CaO catalyst were evaluated by Fourier transform infrared and X-ray diffraction, respectively. There is no change on morphological properties of catalyst between Sr/CaO and pristine CaO. The homogeneous distribution of strontium was confirmed by EDX mapping technique. The specific surface area of powder was estimated to be 10-30 m2 ·g-1. The thermal …
Investigation Of Crosslink Structure Of Natural Rubber During Vulcanization Using X-Ray Absorption Near Edge Spectroscopy,
2020
Chulalongkorn University
Investigation Of Crosslink Structure Of Natural Rubber During Vulcanization Using X-Ray Absorption Near Edge Spectroscopy, Kanoktip Boonkerd, Wanwisa Limphirat
Journal of Metals, Materials and Minerals
The X-ray absorption near edge spectroscopy technique (XANES) has been applied to determine the crosslinking structure of natural rubber (NR) during sulfur vulcanization process. The NR samples were prepared using DCBS as an accelerator at different sulfur to DCBS ratios (from 0.26 to 6.67). The results showed that with increasing cure time from tc50 to tc70, tc90 and tc100 the position of sulfur peak shifted to higher energy. This implied that the amount of polysulfidic crosslink gradually decreased with increasing cure time. This result supported the crosslinking mechanism proposed in the literature at which the polysulfidic crosslink is dominating at …
Influence Of Poly(Butylene Terephthalate) And Wollastonite On Properties Of Recycled Poly(Ethylene Terephthalate) Preforms,
2020
Chulalongkorn University
Influence Of Poly(Butylene Terephthalate) And Wollastonite On Properties Of Recycled Poly(Ethylene Terephthalate) Preforms, Phasawat Chaiwutthinan, Thaksaporn Riyaphan, Athapon Simpraditpan, Amnouy Larpkasemsuk
Journal of Metals, Materials and Minerals
Influence of poly(butylene terephthalate) (PBT) and wollastonite (WLN) on properties of recycled poly(ethylene terephthalate) (RPET) was investigated. RPET was first melt-mixed with PBT at five loadings (10-50 wt%) on a twin screw extruder, and then injection molded. Scanning electron micrographs showed the immiscible blends. The blends at 10-40 wt% PBT displayed droplet-matrix morphology, while the blend at 50 wt% PBT showed a matrix inversion. All blends showed a PBT-dosedependent increase in impact strength and Young's modulus with an expense of tensile strength and elongation at break. Among five RPET/PBT blends, the one at 40 wt% PBT exhibited the good balanced …
Design, Development, And Testing Of A Low Cost, Additively-Manufactured, Centrifugal Compressor,
2020
Air Force Institute of Technology
Design, Development, And Testing Of A Low Cost, Additively-Manufactured, Centrifugal Compressor, Aaron P. Bauer
Theses and Dissertations
The three objectives of this research were to: 1.) design, build, and test AM compressors to substitute into COTS micro-gas turbine engines, 2.) provide initial correlations between FEA and compressor failure speed, and 3.) characterize the effects of AM on compressor performance. These goals improved the design cycle cost and the design-validation time cycle. ULTEM 9085, 300-AMB, and Onyx-Kevlar temperature-dependent tensile properties were measured. FEA-predicted failure speeds of stock compressor designs led design improvements, potentially fulfilling the original compressor requirements. Physical testing of the stock and ULTEM 9085 compressors occurred. Comparing these compressors' performances demonstrated that low cost, AM materials …
Modeling Hybrid Composites Using Tsai-Wu And Hashin Failure Criterion,
2020
Air Force Institute of Technology
Modeling Hybrid Composites Using Tsai-Wu And Hashin Failure Criterion, Candice R. Roberts
Theses and Dissertations
Hybrid composites require further study and testing for future use in various fields. This study focuses on simulating a Hybrid Composite using IM7-977-3 laminae with steel foils in Abaqus under bolt loading by using Hashin and Tsai-Wu failure criterion. Initial simulations contain only the IM7-977-3 composite with cohesive layers. Foil samples were then tested for accurate material properties from which the simulations were then updated to include steel foils. The two models show that Tsai-Wu failure criterion, while great for anisotropic material in tension, does not prove accuracy around the hole of the composite material which is in compression. Hashin …
Fatigue Behavior Of An Advanced Melt-Infiltrated Sic/Sic Composite With Environmental Barrier Coating At 1200°C In Air And In Steam,
2020
Air Force Institute of Technology
Fatigue Behavior Of An Advanced Melt-Infiltrated Sic/Sic Composite With Environmental Barrier Coating At 1200°C In Air And In Steam, Thaddeus M. Williams
Theses and Dissertations
Advanced aerospace applications such as aircraft turbine engine components, hypersonic flight vehicles, and spacecraft reentry thermal protection systems require structural materials that have superior long-term mechanical properties under high temperature, high pressure, and varying environmental factors, such as moisture. Because of their low density, high strength and fracture toughness at high temperatures SiC fiber-reinforced SiC matrix composites are being evaluated for aircraft engine hot-section components. In these applications the composites will be subjected to various types of mechanical loadings at elevated temperatures in oxidizing environments. Because their constituents are intrinsically oxidation-prone, the most significant problem hindering SiC/SiC composites is oxidation …
On The Corrosion Behaviour Of As-Cast And Heat-Treated Mg-Re Alloys In 0.9% Nacl Solution,
2020
Chulalongkorn University
On The Corrosion Behaviour Of As-Cast And Heat-Treated Mg-Re Alloys In 0.9% Nacl Solution, Abdelkader Hanna, Lyacine Rabahi, Mohamed Amine Soualili, Achour Dakhouche, Djamel Bradai, Hiba Azzeddine
Journal of Metals, Materials and Minerals
The microstructure and corrosion behaviour of as-cast and heat-treated Mg-1.44Nd and Mg-1.43Ce (wt.%) alloys in 0.9% NaCl (wt.%) solution were investigated using electrochemical tests, X-ray diffraction (XRD) and scanning electron microscopy, combined with energy-dispersive X-ray spectroscopy (SEM-EDS). The as-cast microstructure of both alloys revealed the presence of second phases. Heat treatment at 535°C for 6 h led to a more uniform distribution of the second phases in Mg-1.44Nd alloy and their dissolution along the grains boundaries in the Mg-1.43Ce alloy. As a result, the corrosion resistance was improved in the heat-treated alloys. Accordingly, the corrosion resistance values for the heat-treated …
Numerical Modeling Of Longwall Top Coal Caving Method At Thar Coalfield,
2020
Chulalongkorn University
Numerical Modeling Of Longwall Top Coal Caving Method At Thar Coalfield, Niaz Muhammad Shahani, Zhijun Wan, Xigui Zheng, Li Guichen, Cancan Liu, Fahad Irfan Siddiqui, Gu Bin
Journal of Metals, Materials and Minerals
Thar Coalfield in Pakistan is the largest reserve of lignite coal in the country, which is outlined by thick coal seams. The preferred mining method for these thick coal seams is the Longwall Top Coal Caving (LTCC). The connection of both the top coal caving and its compactness are still rare; therefore, the capability of top coal caving mechanism is the most significant factor in LTCC that must be adequately explained and examined. Moreover, in order to achieve the ideal coal production, a comprehensive modeling of deformation and induced stress is mandatory. In this study, a 12 m thick coal …
Ten Questions Concerning The Implications Of Carpet On Indoor Chemistry And Microbiology,
2020
The Ohio State University
Ten Questions Concerning The Implications Of Carpet On Indoor Chemistry And Microbiology, Sarah R, Haines, Rachel I. Adams, Brandon E. Boor, Thomas A. Bruton, John Downey, Andrea R. Ferro, Elliott T. Gall, Multiple Additional Authors
Mechanical and Materials Engineering Faculty Publications and Presentations
Carpet and rugs currently represent about half of the United States flooring market and offer many benefits as a flooring type. How carpets influence our exposure to both microorganisms and chemicals in indoor environments has important health implications but is not well understood. The goal of this manuscript is to consolidate what is known about how carpet impacts indoor chemistry and microbiology, as well as to identify the important research gaps that remain. After describing the current use of carpet indoors, questions focus on five specific areas: 1) indoor chemistry, 2) indoor microbiology, 3) resuspension and exposure, 4) current practices …
Solution Anneal Heat Treatments To Enhance Mechanical Performance Of Additively Manufactured Inconel 718,
2020
Air Force Institute of Technology
Solution Anneal Heat Treatments To Enhance Mechanical Performance Of Additively Manufactured Inconel 718, David J. Newell
Theses and Dissertations
The nickel-based superalloy Inconel 718 (IN718) is an excellent candidate among aerospace alloys for laser powder-bed fusion (LPBF) manufacturing. As-built LPBF IN718 has a vertically aligned columnar (001) microstructure which translates into orthotropic mechanical behavior. The post-process heat treatments for IN718 were developed 60 years ago for wrought and cast processes and do not mitigate the columnar microstructure of the LPBF process. Recrystallization is required to remove the columnar microstructure, which would allow for parts to be fabricated on different machines or in different orientations but still achieve the same properties. This research investigated the microstructure of LPBF IN718 as …
Structures And Electrochemical Properties Of Sn-Cl Co-Doped Li2Mno3 As Positive Materials For Lithium Ion Batteries,
2020
1. Powder Metallurgy Research Institute, Central South University, Changsha 410083, China;2. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China;
Structures And Electrochemical Properties Of Sn-Cl Co-Doped Li2Mno3 As Positive Materials For Lithium Ion Batteries, Fei Wang, Huan-Huan Zhai, Du-Dan Wang, Yu-Peng Li, Kang-Hua Chen
Journal of Electrochemistry
Positive material Li2MnO3 shows the highest ratio of lithium to manganese among lithium-rich materials and exhibites the theoretical capacity up to 458 mAh·g-1, making it one of the most promising cathode materials. However, this material has the intrinsic low electrical conductivity and poor cycle stability. In this paper, Li2MnO3, the lithium-rich positive material, was prepared by sol-gel method using acetate as raw material and citric acid as a complexing agent. By using SnC2O4 as a tin source, Sn4+ instead of Mn4+ was introduced to obtain the …
Recent Progress In The Mechanistic Understanding Of Co2 Reduction On Copper,
2020
Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei, 230026, China;
Recent Progress In The Mechanistic Understanding Of Co2 Reduction On Copper, Matthew M Sartin, Wei Chen, Fan He, Yan-Xia Chen
Journal of Electrochemistry
In this review, we present the major developments in the understanding of the mechanisms of the electrochemical reduction of CO2 from a historical perspective. Most of the work discussed in this review was carried out at copper electrodes, as this is the only material at which hydrocarbons are produced in reasonable quantities. The emphasis focuses on the differentiation of mechanisms for the generation of C1 and C2 products as well as factors and methods for controlling the product selectivity of CO2 reduction. We have highlighted ambiguities, assumptions, and important methodologies, such as differential electrochemical mass spectrometry and electrochemical …
Lithium Storage Performance Of High Capacity Material Si@CPzs In Lithium Ion Batteries,
2020
1. Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China;2. University of Chinese Academy of Sciences, Beijing 100080, China;
Lithium Storage Performance Of High Capacity Material Si@CPzs In Lithium Ion Batteries, Qing-Nuan Zhang, Fang-Fang Zhang, Hong-Xia Li, Bing-Jun Yang, Xiao-Cheng Li, Juan Yang
Journal of Electrochemistry
Carbon layers with different thicknesses were introduced into the surfaces of silicon (Si) nanoparticles by sol-gel method using poly (cyclotriphosphazene-co-4, 4'-sulfonyldiphenol) as the carbon source. Technologies of X-ray diffraction, thermo-gravimetric analysis, Brunauer-Emmett-Teller and transmission electron microscopy were employed to analyze the structures and components of the as-prepared Si@CPZS composites. Electrochemical performance of Si@CPZS with different carbon thicknesses was studied. The results showed that Si@CPZS with carbon thickness of 10 nm possessed the best performance. Its capacity remained 940 mAh·g-1 after 290 cycles under 500 mA·g-1. As the addictive, the graphite-based anode contained 30% of …
Preparations Of Nickel-Iron Hydroxide/Sulfide And Their Electrocatalytic Performances For Overall Water Splitting,
2020
1. College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China;
Preparations Of Nickel-Iron Hydroxide/Sulfide And Their Electrocatalytic Performances For Overall Water Splitting, Hang-Shuo Lu, Xiao-Bo He, Feng-Xiang Yin, Guo-Ru Li
Journal of Electrochemistry
The Ni-Fe/Ti oxygen evolution electrode was prepared by electrodeposition on a titanium mesh substrate. Then, the as prepared Ni-Fe/Ti electrode was used to derive the Ni-Fe-S/Ti hydrogen evolution electrode through solid phase sulfuration. The effects of the molar ratio of Ni2+ to Fe3+ in the electrolyte and the amount of thiourea on the structures and electrochemical performances of Ni-Fe/Ti and Ni-Fe-S/Ti electrodes were investigated. The results show that the oxygen evolution performance of Ni-Fe/Ti electrode was first increased and then decreased with the increase of nickel ion content in the electrolyte. The Ni9Fe1/Ti electrode exhibited the best oxygen …
